title: Effect of dexmedetomidine, morphine-lidocaine-ketamine, and dexmedetomidine-morphine-lidocaine-ketamine constant rate infusions on the minimum alveolar concentration of isoflurane and bispectral index in dogs.
abstract: OBJECTIVE
  To determine the effect of dexmedetomidine, morphine-lidocaine-ketamine (MLK), and dexmedetomidine-morphine-lidocaine-ketamine (DMLK) constant rate infusions on the minimum alveolar concentration (MAC) of isoflurane and bispectral index (BIS) in dogs.
  
  
  METHODS
  6 healthy adult dogs.
  
  
  METHODS
  Each dog was anesthetized 4 times with a 7-day washout period between anesthetic episodes. During the first anesthetic episode, the MAC of isoflurane (baseline) was established. During the 3 subsequent anesthetic episodes, the MAC of isoflurane was determined following constant rate infusion of dexmedetomidine (0.5 μg/kg/h), MLK (morphine, 0.2 mg/kg/h; lidocaine, 3 mg/kg/h; and ketamine, 0.6 mg/kg/h), or DMLK (dexmedetomidine, 0.5 μg/kg/h; morphine, 0.2 mg/kg/h; lidocaine, 3 mg/kg/h; and ketamine 0.6 mg/kg/h). Among treatments, MAC of isoflurane was compared by means of a Friedman test with Conover posttest comparisons, and heart rate, direct arterial pressures, cardiac output, body temperature, inspired and expired gas concentrations, arterial blood gas values, and BIS were compared with repeated-measures ANOVA and a Dunn test for multiple comparisons.
  
  
  RESULTS
  Infusion of dexmedetomidine, MLK, and DMLK decreased the MAC of isoflurane from baseline by 30%, 55%, and 90%, respectively. Mean heart rates during dexmedetomidine and DMLK treatments was lower than that during MLK treatment. Compared with baseline values, mean heart rate decreased for all treatments, arterial pressure increased for the DMLK treatment, cardiac output decreased for the dexmedetomidine treatment, and BIS increased for the MLK and DMLK treatments. Time to extubation and sternal recumbency did not differ among treatments.
  
  
  CONCLUSIONS
  Infusion of dexmedetomidine, MLK, or DMLK reduced the MAC of isoflurane in dogs.
authors.affiliation: Department of Veterinary Clinical Sciences, College of Veterinary Medicine, The Ohio State University, Columbus, OH 43210, USA. lisasamsdvm@yahoo.com
authors.forename: Lisa Sams
authors.initials: LS
authors.lastname: Ebner
authors.forename: Phillip
authors.initials: P
authors.lastname: Lerche
authors.forename: Richard M
authors.initials: RM
authors.lastname: Bednarski
authors.forename: John A E
authors.initials: JA
authors.lastname: Hubbell
mesh_terms: D018712:Analgesics, Non-Narcotic / Q000008:administration & dosage / Q000494:pharmacology; D000701:Analgesics, Opioid / Q000008:administration & dosage / Q000494:pharmacology; D000778:Anesthetics, Dissociative / Q000008:administration & dosage / Q000494:pharmacology; D018685:Anesthetics, Inhalation / Q000008:administration & dosage / Q000494:pharmacology*; D000779:Anesthetics, Local / Q000008:administration & dosage / Q000494:pharmacology; D000818:Animals; D056805:Consciousness Monitors; D018592:Cross-Over Studies; D020927:Dexmedetomidine / Q000008:administration & dosage / Q000494:pharmacology; D004285:Dogs / Q000097:blood*; D004347:Drug Interactions; D004359:Drug Therapy, Combination; D005260:Female; D007530:Isoflurane / Q000493:pharmacokinetics*; D007649:Ketamine / Q000008:administration & dosage / Q000494:pharmacology*; D008012:Lidocaine / Q000008:administration & dosage / Q000494:pharmacology*; D008297:Male; D009020:Morphine / Q000008:administration & dosage / Q000494:pharmacology*; D011650:Pulmonary Alveoli
chemical_list: D018712:Analgesics, Non-Narcotic; D000701:Analgesics, Opioid; D000778:Anesthetics, Dissociative; D018685:Anesthetics, Inhalation; D000779:Anesthetics, Local; D020927:Dexmedetomidine; D007649:Ketamine; D009020:Morphine; D008012:Lidocaine; D007530:Isoflurane